Tenant deletion API does not purge database schema

Overview:

Delete tenant with purge=true. Noticed that the database schema mod_remote_storage remains.

Steps to Reproduce:

1. Create a tenant and enable mod-remote-storage for it
2. Delete the tenant with purge=true 
3. Check db and notice <tenantId>_mod_remote_storage schema

Expected Results:

<tenantId>_mod_remote_storage schema should be dropped

Actual Results:

<tenantId>_mod_remote_storage schema is NOT dropped

Note: unit tests to be implemented.